That is indeed his argument

That is indeed his argument, Arvind. In Sachs's book The End of Poverty, he discusses the problems with Western attempts to understand the political, economical and physical climates of developing countries. He points out that medicine is practiced clinically, where doctors immerse themselves in the community they wish to treat, and thereby creates the analogy of a "clinical economist." Economists cannot very well "treat" the economy they wish to improve by means of second hand data. Similarly, one can create the analogy of a "clinical designer," one who is ready to immerse him or herself in the climate he or she wants to 'treat.' Sachs denounces the use of typical social research methods and second-hand data, and would agree wholeheartedly with your post.